WEBVTT 1 00:00.000 --> 00:07.480 So to begin here, let's jump in and take a look at some of the general 2 00:07.480 --> 00:08.200 characteristics 3 00:08.200 --> 00:11.720 and attributes of our overlay routing. 4 00:11.720 --> 00:15.160 We'll talk about the different protocols that commonly get used. 5 00:15.160 --> 00:17.790 And then I want to jump into the topology that we're going to be using 6 00:17.790 --> 00:18.560 throughout this 7 00:18.560 --> 00:22.630 skill so that we're used to it a little bit when we get into actually troubles 8 00:22.630 --> 00:23.320 hooting some 9 00:23.320 --> 00:24.800 of our protocols. 10 00:24.800 --> 00:30.850 So that said, let's jump in and take a look at some of the basics of our WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 10 00:24.800 --> 00:30.850 So that said, let's jump in and take a look at some of the basics of our 11 00:30.850 --> 00:32.160 overlay networking. 12 00:32.160 --> 00:37.280 So one of our first considerations with our overlay routing is going to be how 13 00:37.280 --> 00:37.880 is it going 14 00:37.880 --> 00:39.400 to be managed? 15 00:39.400 --> 00:42.160 And we really sort of have two choices here. 16 00:42.160 --> 00:45.720 First, it can be managed by the administrator. 17 00:45.720 --> 00:50.230 That would be you, which means we're basically going to be manually running the 18 00:50.230 --> 00:51.040 routing for 19 00:51.040 --> 00:53.000 our overlay network. 20 00:53.000 --> 00:58.760 The other choice is to implement SDN or software defined networking. 21 00:58.760 --> 01:05.720 Now in this course, the example we've been using is Cisco's SDWAN product. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 21 00:58.760 --> 01:05.720 Now in this course, the example we've been using is Cisco's SDWAN product. 22 01:05.720 --> 01:11.260 SDWAN, of course, is an SDN environment designed specifically for wide-area 23 01:11.260 --> 01:12.320 networks. 24 01:12.320 --> 01:17.320 Now troubleshooting SDWAN is not going to be the focus of this skill. 25 01:17.320 --> 01:20.240 We will be getting to that in a future skill. 26 01:20.240 --> 01:26.450 So we're really going to be focusing on the administrator managed network for 27 01:26.450 --> 01:27.200 this skill. 28 01:27.200 --> 01:32.330 Something else to keep in mind, the underlay and the overlay routing are WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 28 01:27.200 --> 01:32.330 Something else to keep in mind, the underlay and the overlay routing are 29 01:32.330 --> 01:34.040 usually kept completely 30 01:34.040 --> 01:35.040 separate. 31 01:35.040 --> 01:37.280 Now there's a few ways to do this. 32 01:37.280 --> 01:40.640 Of course, the biggest one, we could use VRFs. 33 01:40.640 --> 01:46.350 A VRF will of course keep these separate, but this can also create some 34 01:46.350 --> 01:47.600 complexity if 35 01:47.600 --> 01:53.120 we do need to do route leaking from the underlay to the overlay for perhaps 36 01:53.120 --> 01:54.400 something like 37 01:54.400 --> 01:56.040 internet access. 38 01:56.040 --> 02:00.800 The other choice is we can simply do this with route filtering. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 38 01:56.040 --> 02:00.800 The other choice is we can simply do this with route filtering. 39 02:00.800 --> 02:04.760 Route filtering is actually where we're going to be doing it in this skill, but 40 02:04.760 --> 02:05.440 of course 41 02:05.440 --> 02:09.700 we could implement VRFs if we wanted to, but we're mostly going to be looking 42 02:09.700 --> 02:10.720 at filtering. 43 02:10.720 --> 02:15.890 And again, the main reason we need to do this is the underlay is often going to 44 02:15.890 --> 02:16.800 be internet 45 02:16.800 --> 02:17.800 routing. 46 02:17.800 --> 02:22.000 So maybe just a static route pointing to your service provider. 47 02:22.000 --> 02:27.410 Maybe we're getting full BGP routes or partial BGP tables, but whatever we're 48 02:27.410 --> 02:28.240 doing to get 49 02:28.240 --> 02:31.880 to the internet, that's going to be the underlay. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 49 02:28.240 --> 02:31.880 to the internet, that's going to be the underlay. 50 02:31.880 --> 02:38.040 The overlay is often going to be comprised of private IP addresses. 51 02:38.040 --> 02:44.910 That's of course your 192.168, you're 172.16 to 172.31, and of course, you're 52 02:44.910 --> 02:46.160 10 networks. 53 02:46.160 --> 02:52.090 The problem with this, of course, is these networks are not allowed on the 54 02:52.090 --> 02:53.200 internet. 55 02:53.200 --> 02:57.280 So since they're not allowed on the internet, that's where our filtering has to 56 02:57.280 --> 02:57.880 come into 57 02:57.880 --> 02:59.040 play. 58 02:59.040 --> 03:02.910 We need to make sure that our private IP addresses don't get leaked out to the WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 58 02:59.040 --> 03:02.910 We need to make sure that our private IP addresses don't get leaked out to the 59 03:02.910 --> 03:03.880 internet, and 60 03:03.880 --> 03:08.050 most likely we probably want to make sure that our internet routing, 61 03:08.050 --> 03:09.120 particularly if 62 03:09.120 --> 03:13.170 we're getting full internet tables, we want to make sure that doesn't get 63 03:13.170 --> 03:13.920 leaked into 64 03:13.920 --> 03:15.600 the overlay networking. 65 03:15.600 --> 03:19.310 So for the most part, we want to keep these separate, although there could of 66 03:19.310 --> 03:19.880 course be 67 03:19.880 --> 03:21.640 some exceptions. 68 03:21.640 --> 03:27.540 Now of course, in an SD-WAN environment, OMP or overlay management protocol is 69 03:27.540 --> 03:28.040 going to 70 03:28.040 --> 03:30.360 be used in the overlay. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 70 03:28.040 --> 03:30.360 be used in the overlay. 71 03:30.360 --> 03:33.360 And again, we're not going to look at that in this skill, but I just wanted to 72 03:33.360 --> 03:33.880 mention 73 03:33.880 --> 03:38.240 it so we understand that SD-WAN is going to be a little bit different from what 74 03:38.240 --> 03:38.560 we're 75 03:38.560 --> 03:41.560 going to be looking at in this skill. 76 03:41.560 --> 03:47.180 We're going to be looking at more of a traditional or administrator controlled 77 03:47.180 --> 03:47.680 WAN. 78 03:47.680 --> 03:51.920 And in these environments, we're generally going to see three protocols 79 03:51.920 --> 03:53.640 commonly used. 80 03:53.640 --> 03:56.080 First is going to be BGP. 81 03:56.080 --> 04:01.360 Now BGP could be used in one of two ways, and really probably more than that. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 81 03:56.080 --> 04:01.360 Now BGP could be used in one of two ways, and really probably more than that. 82 04:01.360 --> 04:06.990 But the two main things we'll see BGP used for is as we mentioned before, our 83 04:06.990 --> 04:07.520 internet 84 04:07.520 --> 04:12.080 routing and possibly for the overlay. 85 04:12.080 --> 04:15.820 Now of course, our main focus here is going to be on the overlay, but we're 86 04:15.820 --> 04:16.240 going to see 87 04:16.240 --> 04:21.760 it a little bit used with internet as well as we look at our existing topology. 88 04:21.760 --> 04:23.800 Next is going to be OSPF. 89 04:23.800 --> 04:28.960 OSPF is going to be almost entirely used for the overlay. 90 04:28.960 --> 04:34.240 Now it'll be used on the LAN as well, but right now we're focusing on the WAN. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 90 04:28.960 --> 04:34.240 Now it'll be used on the LAN as well, but right now we're focusing on the WAN. 91 04:34.240 --> 04:37.720 So for the WAN, this is just going to be the overlay. 92 04:37.720 --> 04:42.960 You're not going to be running OSPF with your service provider in most cases. 93 04:42.960 --> 04:46.620 There are a few out there that make an exception, but more than likely you're 94 04:46.620 --> 04:47.640 going to be running 95 04:47.640 --> 04:53.630 BGP with your service provider, or of course, the final option, just using 96 04:53.630 --> 04:54.560 static. 97 04:54.560 --> 04:58.720 The advantage of static routing, of course, is you can use it everywhere. 98 04:58.720 --> 05:02.360 The downside, of course, well, it's static, which means you as the WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 98 04:58.720 --> 05:02.360 The downside, of course, well, it's static, which means you as the 99 05:02.360 --> 05:03.560 administrator, you 100 05:03.560 --> 05:07.280 as the administrator need to maintain these tables. 101 05:07.280 --> 05:12.140 So this is going to be used for maybe things like if you just have one cloud 102 05:12.140 --> 05:12.920 connection 103 05:12.920 --> 05:16.910 going to one network that has servers on it, well, you could get away with a 104 05:16.910 --> 05:18.560 static route. 105 05:18.560 --> 05:24.160 So this is going to be good for smaller, more stable, or static environments. 106 05:24.160 --> 05:29.040 Now as far as which ones you can use, of course, you can always use static. 107 05:29.040 --> 05:33.650 As we said, OSPF is going to be for the overlay, but all of our major cloud WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 107 05:29.040 --> 05:33.650 As we said, OSPF is going to be for the overlay, but all of our major cloud 108 05:33.650 --> 05:34.560 providers, so 109 05:34.560 --> 05:39.490 certainly all the ones we've discussed in this course, so AWS, Microsoft Azure, 110 05:39.490 --> 05:39.760 and 111 05:39.760 --> 05:45.560 of course, Google Cloud, these all support BGP for the overlay. 112 05:45.560 --> 05:50.950 Again, keeping in mind, BGP for the underlay is simply between you and your 113 05:50.950 --> 05:52.560 service provider. 114 05:52.560 --> 05:56.680 That's not generally going to have anything to do with the cloud providers. 115 05:56.680 --> 06:02.560 One thing to keep in mind here, you can in fact mix these together, but keep in WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 115 05:56.680 --> 06:02.560 One thing to keep in mind here, you can in fact mix these together, but keep in 116 06:02.560 --> 06:03.040 mind 117 06:03.040 --> 06:08.780 if you do, you're often going to have to do redistribution between the routing 118 06:08.780 --> 06:09.880 protocols. 119 06:09.880 --> 06:15.520 And if you do that, the routes are going to have to be very carefully filtered. 120 06:15.520 --> 06:20.410 Again, for the reasons we mentioned above that we don't want to leak routes 121 06:20.410 --> 06:21.160 from internet 122 06:21.160 --> 06:23.720 to private, private to internet. 123 06:23.720 --> 06:28.180 Another example is we may or may not need to leak our cloud routes into the 124 06:28.180 --> 06:28.840 rest of our 125 06:28.840 --> 06:29.840 network. 126 06:29.840 --> 06:32.440 It depends if we're default routing to an edge. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 126 06:29.840 --> 06:32.440 It depends if we're default routing to an edge. 127 06:32.440 --> 06:36.520 We'll discuss that more in just a minute as we jump into our topology. 128 06:36.520 --> 06:39.640 So that said, let's go ahead and do just that. 129 06:39.640 --> 06:43.660 So this is the topology that we're going to be working with throughout this 130 06:43.660 --> 06:44.040 skill. 131 06:44.040 --> 06:47.840 And there's a few things we want to make sure we're clear on as we jump in. 132 06:47.840 --> 06:54.440 First is we have BGP AS 3112 here in the middle. 133 06:54.440 --> 06:57.520 That's basically acting as our service provider. 134 06:57.520 --> 07:00.280 This is acting as service provider one. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 134 06:57.520 --> 07:00.280 This is acting as service provider one. 135 07:00.280 --> 07:06.600 Then we have all of our customer sites, which are all going to be 65, 001 and 136 07:06.600 --> 07:07.840 acting as 137 07:07.840 --> 07:10.160 the headquarters over here on the left. 138 07:10.160 --> 07:16.120 And then we just have a site 100 and a site 110 over here on the right. 139 07:16.120 --> 07:19.760 Next up, we have BGP peers. 140 07:19.760 --> 07:24.400 And the way we have our peering is almost identical to the physical links. 141 07:24.400 --> 07:28.710 So we have router three is peering with router one, router four is peering with 142 07:28.710 --> 07:30.560 router two, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 142 07:28.710 --> 07:30.560 router two, 143 07:30.560 --> 07:35.740 router one is peering with router two, router one and router seven are peered 144 07:35.740 --> 07:36.280 and router 145 07:36.280 --> 07:38.520 two and router eight are peered. 146 07:38.520 --> 07:46.170 So this represents our BGP peering inside of each of our locations is running O 147 07:46.170 --> 07:47.360 SPF headquarters 148 07:47.360 --> 07:51.640 is operating as our OSPF area zero. 149 07:51.640 --> 08:00.720 Site 100 is going to be also area 100 and site 110 is OSPF area 110. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 149 07:51.640 --> 08:00.720 Site 100 is going to be also area 100 and site 110 is OSPF area 110. 150 08:00.720 --> 08:05.280 We currently have IP sec tunnels running from router three to router seven, 151 08:05.280 --> 08:05.840 router three 152 08:05.840 --> 08:12.880 to router eight, router four to router seven and router four to router eight. 153 08:12.880 --> 08:20.160 These tunnels are in the respective OSPF areas for the remote site. 154 08:20.160 --> 08:27.390 That means that in this environment, router three and router four are acting as 155 08:27.390 --> 08:28.280 our OSPF 156 08:28.280 --> 08:30.240 area border routers. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 156 08:28.280 --> 08:30.240 area border routers. 157 08:30.240 --> 08:35.600 There tunnels are in the area for the remote site and the inside interfaces in 158 08:35.600 --> 08:36.620 headquarters 159 08:36.620 --> 08:39.840 are in OSPF area zero. 160 08:39.840 --> 08:46.480 Also as a note, these remote site areas are running as OSPF stub areas. 161 08:46.480 --> 08:49.780 If you're not completely familiar with what this means, we'll be discussing 162 08:49.780 --> 08:50.200 this in a 163 08:50.200 --> 08:53.120 video coming up next. 164 08:53.120 --> 08:55.960 Also just to wrap up our IP sec tunnels. 165 08:55.960 --> 09:03.350 We also have IP sec tunnels from router three up to AWS and from router four up WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 165 08:55.960 --> 09:03.350 We also have IP sec tunnels from router three up to AWS and from router four up 166 09:03.350 --> 09:04.400 to AWS. 167 09:04.400 --> 09:09.320 So this is how we have our VPN tunnels and our IGP's. 168 09:09.320 --> 09:16.520 Also be aware that over that IP sec tunnel, we are also running a BGP session 169 09:16.520 --> 09:17.480 with AWS. 170 09:17.480 --> 09:22.650 Now that means that routers three and four are primarily acting as our edge 171 09:22.650 --> 09:24.120 routers and 172 09:24.120 --> 09:27.560 they're acting as our connection out to the internet. 173 09:27.560 --> 09:31.720 So routers seven and eight, for example, if they want to go to the internet or WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 173 09:27.560 --> 09:31.720 So routers seven and eight, for example, if they want to go to the internet or 174 09:31.720 --> 09:32.280 the sites 175 09:32.280 --> 09:35.430 behind them want to go to the internet, they are first going to go through 176 09:35.430 --> 09:36.080 routers three 177 09:36.080 --> 09:41.240 and four and then go out either to the internet or out to AWS. 178 09:41.240 --> 09:45.580 So let's clean this up a little bit and talk about a little bit more detail 179 09:45.580 --> 09:45.920 here. 180 09:45.920 --> 09:51.590 Also be aware that on the outside interfaces of both router three and router 181 09:51.590 --> 09:52.600 four, these 182 09:52.600 --> 09:54.520 are operating under net. 183 09:54.520 --> 09:58.960 So these are doing that overload on both of these interfaces. 184 09:58.960 --> 10:03.880 Therefore hiding all the private addresses from going out to the internet. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 184 09:58.960 --> 10:03.880 Therefore hiding all the private addresses from going out to the internet. 185 10:03.880 --> 10:10.420 Also be aware that router three and router four are both doing redistribution 186 10:10.420 --> 10:12.360 from OSPF 187 10:12.360 --> 10:17.360 into BGP going out towards AWS. 188 10:17.360 --> 10:22.570 This is how AWS is going to learn how to get to each of these networks out here 189 10:22.570 --> 10:23.120 behind 190 10:23.120 --> 10:24.920 each of these routers. 191 10:24.920 --> 10:29.480 So all of this information is going to be sent out to AWS. 192 10:29.480 --> 10:36.080 Now what we're not going to be doing is redistributing the BGP into OSPF. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 192 10:29.480 --> 10:36.080 Now what we're not going to be doing is redistributing the BGP into OSPF. 193 10:36.080 --> 10:37.960 We don't need to. 194 10:37.960 --> 10:44.520 That's simply because routers three and four are also sending out default 195 10:44.520 --> 10:45.560 routes. 196 10:45.560 --> 10:49.560 They're sending out the default routes into area zero. 197 10:49.560 --> 10:52.880 They're sending it across the tunnels out to the other areas. 198 10:52.880 --> 10:58.330 So basically everything on our inside network is going to default route to 199 10:58.330 --> 10:59.120 either routers 200 10:59.120 --> 11:00.920 three or four. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 200 10:59.120 --> 11:00.920 three or four. 201 11:00.920 --> 11:05.960 Once they get to three and four, three and four know how to get to AWS because 202 11:05.960 --> 11:06.520 they are 203 11:06.520 --> 11:08.960 running BGP with AWS. 204 11:08.960 --> 11:12.600 So they know how to get to this server network back here. 205 11:12.600 --> 11:16.920 So in this example, we only have to do one way redistribution. 206 11:16.920 --> 11:20.290 Now of course, if we were designing our routing a little bit differently, that 207 11:20.290 --> 11:20.880 may not be the 208 11:20.880 --> 11:25.000 case, but this is what we're going to be doing for our example. 209 11:25.000 --> 11:28.890 Also be aware, just in case you happen to see it in the configs, it's not 210 11:28.890 --> 11:29.640 really going 211 11:29.640 --> 11:32.280 to affect our lab here today. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 211 11:29.640 --> 11:32.280 to affect our lab here today. 212 11:32.280 --> 11:40.240 However, be aware that we are running VRRP on the gigabit one interface of both 213 11:40.240 --> 11:41.000 R1 and 214 11:41.000 --> 11:42.880 R2. 215 11:42.880 --> 11:48.170 And the reason we're doing this is because all of the traffic coming in to the 216 11:48.170 --> 11:49.800 204.186 217 11:49.800 --> 11:55.310 networks, all of these networks down here, these are all simply being forwarded 218 11:55.310 --> 11:55.720 on this 219 11:55.720 --> 12:03.000 19 address by our path device, and it's going to the address of VRRP. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 219 11:55.720 --> 12:03.000 19 address by our path device, and it's going to the address of VRRP. 220 12:03.000 --> 12:06.140 So simply because we're doing forwarding to one address, and there's not 221 12:06.140 --> 12:07.080 actually a routing 222 12:07.080 --> 12:14.360 protocol between the path device and R1 and R2, it's simply running VRRP. 223 12:14.360 --> 12:18.270 So those are all the important aspects of the topology that we'll be using 224 12:18.270 --> 12:19.000 throughout 225 12:19.000 --> 12:20.200 this skill. 226 12:20.200 --> 12:24.440 Of course, we'll be looking at these aspects in more detail as we go through. 227 12:24.440 --> 12:26.800 We'll see them on the command line and so on. 228 12:26.800 --> 12:30.760 This is just an overview to know what to expect. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000 228 12:26.800 --> 12:30.760 This is just an overview to know what to expect. 229 12:30.760 --> 12:37.200 So in this video, we just jumped in and got an overview of our overlay routing, 230 12:37.200 --> 12:37.480 and we 231 12:37.480 --> 12:41.680 took a look at the topology that we're going to be using throughout this skill, 232 12:41.680 --> 12:42.040 so we know 233 12:42.040 --> 12:43.440 what to expect. 234 12:43.440 --> 12:48.250 Next, let's jump in and take a look at some of the aspects of OSPF that we want 235 12:48.250 --> 12:48.640 to be 236 12:48.640 --> 12:51.400 aware of as we jump into troubleshooting it. 237 12:51.400 --> 12:58.780 >> Okay.